Motion picture encoding apparatus and method thereof

ABSTRACT

Provided is a video encoding apparatus, including a signal separator to separate a differential image block into a first domain and a second domain, based on a boundary line included in the differential image block, the differential image block indicating a difference between an original image and a prediction image with respect to the original image, a transform encoder to perform a transform encoding with respect to the first domain using a discrete cosine transform (DCT), a quantization unit to quantize an output of the transform encoding unit in a frequency domain, a space domain quantization unit to quantize the second domain in a space domain, and an entropy encoder to perform an entropy encoding using outputs of the quantization unit and the space domain quantization unit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation Application of Ser. No. 15/049,854filed Feb. 22, 2016, which is continuation Application of Ser. No.14/821,862 filed Aug. 10, 2015, which is a continuation Application ofSer. No. 14/040,132 filed on Sep. 27, 2013, which is a continuation ofapplication Ser. No. 13/389,324 having a 371(c) date of Oct. 2, 2012,which is a U.S. national stage application of International ApplicationNo. PCT/KR2010/005186 filed on Aug. 6, 2010. This application claims thebenefit of Korean Applications Nos. 10-2009-0072630 filed on Aug. 7,2009; 10-2009-0128064 filed on Dec. 21, 2009; and 10-2010-0075931 filedon Aug. 6, 2010. The entire contents of application Ser. Nos.15/049,854, 14/821,862, 14/040,132, 13/389,324, InternationalApplication No. PCT/KR2010/005186, and Korean Application Nos.10-2009-0072630, 10-2009-0128064, and 10-2010-0075931 are incorporatedherein by reference for all purposes.

TECHNICAL FIELD

Technical Background

The present invention relates to a video encoding apparatus and a videoencoding method.

Background Art

Due to studies of Moving Picture Experts Group (MPEG) of InternationalOrganization for Standardization (ISO/IEC) and Video Coding ExpertsGroup (VCEG) of International Telecommunication Union TelecommunicationStandardization Sector (ITU-T) as organizations for standardization forvideo compression, a number of standards such as H.261, H.263, H.264,MPEG-1, MPEG-2, and MPEG-4 have been developed. Even though a slightdifference may exist, the standards have structures including anestimation and compensation of movement, transform encoding,quantization, entropy coding, and in-loop filtering.

In particular, each standard may use various block sizes associated witha transform encoding, and, usually, a discrete cosine transform (DCT)scheme is commonly adopted and used.

Generally, DCT uses a block, including a pixel value of a differentialimage, as an input, and a performance of DCT is known to be better as acorrelation between pixel values inside of the block becomes greater.

However, since the existing video compression standardizationunconditionally performs the transform encoding and a frequency domainquantization with respect to a differential image block obtained afterperforming a movement prediction, when a boundary domain is includedinside of the differential image block, an amount of transforms to beprocessed is so large that a compression efficiency may decrease.

Accordingly, a new encoding scheme may be required so that thecompression efficiency may not decrease even when the boundary domain isincluded inside of the differential image block.

DISCLOSURE OF INVENTION

Technical Goals

An aspect of the present invention provides a video encoding apparatusand video encoding method capable of minimizing a decrease of anencoding efficiency due to a boundary domain, in consideration of acharacteristic of a differential image block indicating a differencebetween an original image and a prediction image with respect to theoriginal image.

An aspect of the present invention provides a video encoding apparatusand video encoding method capable of enhancing an encoding efficiency,using an adaptive block partition.

An aspect of the present invention provides a video encoding apparatusand video encoding method performing a transform encoding with respectto both of a boundary domain and non-boundary domain to enhance acorrelation between differential image blocks.

Technical Solutions

According to an aspect of the present invention, there is provided avideo encoding apparatus, including a signal separator to separate adifferential image block into a first domain and a second domain, basedon a boundary line included in the differential image block, thedifferential image block indicating a difference between an originalimage and a prediction image with respect to the original image, atransform encoder to perform a transform encoding with respect to thefirst domain using a discrete cosine transform (DCT), a quantizationunit to quantize an output of the transform encoding unit in a frequencydomain, a space domain quantization unit to quantize the second domainin a space domain, and an entropy encoder to perform an entropy encodingusing outputs of the quantization unit and the space domain quantizationunit.

According to an aspect of the present invention, there is provided avideo encoding apparatus, including a signal separator to separate adifferential image block into a first domain and a second domain, basedon a boundary line included in the differential image block, thedifferential image block indicating a difference between an originalimage and a prediction image with respect to the original image, aadaptive transform encoder to perform a transform encoding with respectto the first domain using a DCT, a quantization unit to quantize anoutput of the adaptive transform encoding unit in a frequency domain, aspace domain quantization unit to quantize the second domain in a spacedomain, and an entropy encoder to perform an entropy encoding usingoutputs of the quantization unit and the space domain quantization unit.

According to an aspect of the present invention, there is provided avideo encoding apparatus, including a signal separator to separate adifferential image block into a first domain and a second domain, basedon a boundary line included in the differential image block, thedifferential image block indicating a difference between an originalimage and a prediction image with respect to the original image, a spacedomain quantization unit to quantize the second domain in a spacedomain, a transform encoder to perform a transform encoding with respectto the second domain quantized in the space domain and the first domain,using a DCT, a quantization unit to quantize an output of the transformencoding unit in a frequency domain, and an entropy encoder to performan entropy encoding using an output of the quantization unit.

According to an aspect of the present invention, there is provided avideo encoding method, including separating a differential image blockinto a first domain and a second domain, based on a boundary lineincluded in the differential image block, the differential image blockindicating a difference between an original image and a prediction imagewith respect to the original image, performing a transform encoding withrespect to the first domain using a DCT, quantizing a result of thetransform encoding in a frequency domain, quantizing the second domainin a space domain, and performing an entropy encoding using a quantizedresult in the frequency domain and a quantized result in the spacedomain.

According to an embodiment of the present invention, by separating adifferential image block into a non-boundary domain and boundary domainbased on a boundary line included in the differential image block toincrease an energy compaction, a number of transform efficiencies to beencoded after a quantization may be decreased.

According to an embodiment of the present invention, by separating adifferential image block into a non-boundary domain and boundary domainbased on a boundary line included in the differential image block, acompression efficiency or encoding efficiency of a video image may beenhanced.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram illustrating a video encoding apparatusaccording to an embodiment of the present invention.

FIG. 2 through FIG. 5 are diagrams illustrating that the video encodingapparatus of FIG. 1 separates a differential image block into anon-boundary domain and boundary domain, based on a form of boundaryline included in the differential image block.

FIG. 6 is a block diagram illustrating a video encoding apparatusaccording to another embodiment of the present invention.

FIG. 7 and FIG. 8 are diagrams illustrating that the video encodingapparatus of FIG. 6 separates a differential image block into anon-boundary domain and boundary domain, using an adaptive blockpartition and based on a form of boundary line included in thedifferential image block.

FIG. 9 is a block diagram illustrating a video encoding apparatusaccording to still another embodiment of the present invention.

FIG. 10 is a diagram illustrating that the video encoding apparatus ofFIG. 9 separates a differential image block into a non-boundary domainand boundary domain, based on a form of boundary line included in thedifferential image block.

FIG. 11 is a diagram illustrating a scanning scheme with respect to aquantization result in a case of performing a space domain quantizationin FIG. 10.

FIG. 12 is a flowchart illustrating a video encoding method according toan embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Reference will now be made in detail to embodiments of the presentinvention, examples of which are illustrated in the accompanyingdrawings, wherein like reference numerals refer to the like elementsthroughout. The embodiments are described below in order to explain thepresent invention by referring to the figures.

FIG. 1 is a block diagram illustrating a video encoding apparatusaccording to an embodiment of the present invention.

Referring to FIG. 1, the video encoding apparatus may include an imageprediction unit 110, a subtracter 120, an encoder 130, an adder 140, adecoder 150, a filter 160, a reorder unit 170, and an entropy encoder180.

The image prediction unit 110 may generate a prediction image withrespect to an original image currently being a target for encoding, andmay include a movement prediction unit (ME) 111, a movement compensator(MC) 113, an intra prediction chooser 115, and intra prediction unit117. A high efficiency video coding (HEVC) standard document may bereferred regarding to each component of the image prediction unit 110.

The subtracter 120 may generate a differential image block using theoriginal image and the prediction image. The subtracter 120 may generatethe differential image block by subtracting the prediction imagegenerated in the image prediction unit 110 from the original imagetargeted to be encoded.

The image prediction unit 110 may generate the prediction image bypredicting or estimating a movement to encode a predetermined size ofimage block in a current frame (F_(n)) targeted to be encoded, and thesubtracter 120 may generate a differential image block (D_(n)) bysubtracting the prediction image from the predetermined size of imageblock.

The encoder 130 may encode the differential image block (D_(n)) so thatthe differential image block (D_(n)) may be used for restoring thedifferential image block in the decoder 150 corresponding to the encoder130.

The encoder 130 may include a signal separator 131, a transform encoder133, a quantization unit 135, and a space domain quantization unit 137.

The signal separator 131 may separate the differential image block intoa first domain and a second domain, based on a boundary line included inthe differential image block. Here, the differential image block mayindicate a difference between the original image and the predictionimage with respect to the original image.

Also, the first domain indicates a domain excluding the boundary line,that is a non-boundary domain, and the second domain indicates a domainincluding the boundary line, that is a boundary domain.

The boundary domain may correspond to a domain including the boundaryline of block separation for a movement compensation and a prediction ina screen.

The signal separator 131 may set the domain excluding the boundary lineincluded in the differential image block as the non-boundary domain, andmay set the domain including the boundary line as the boundary domain.The differential image block may be separated into two domains, that is,the boundary domain and non-boundary domain, through the signalseparator 131. The video encoding apparatus may separately transmitsignal separation information to the decoder 150 to separate the domainin the signal separator 151 of the decoder 150, similar to the signalseparator 131 in the encoder 130.

The signal separation information may include at least one of coordinateinformation indicating locations of the non-boundary domain and theboundary domain, and an indicator indicating a domain to which eachblock included in the non-boundary domain and the boundary domainbelongs, between the non-boundary domain and the boundary domain.

Thereafter, a transform encoding and quantization may be performed withrespect to the non-boundary domain, and a space domain quantization maybe performed with respect to the boundary domain.

The signal separator 131 may separate the differential image block intothe boundary domain and the non-boundary domain so that a number ofblocks included in the boundary domain may be a minimum.

The transform encoder 133 may perform a transform encoding with respectto the non-boundary domain using a discrete cosine transform (DCT).

The quantization unit 135 may quantize an output, that is, the discretecosine transformed non-boundary domain, of the transform encoding unit133 in a frequency domain.

The space domain quantization unit 137 may quantize the boundary domainin a space domain.

Signals inputted to each of the quantization unit 135 and the spacedomain quantization unit 137 may have the same values as signalsoutputted from the quantization unit 135 and the space domainquantization unit 137.

When a signal inputted to the quantization unit 135 or the space domainquantization unit 137 is one-to-one mapped to a signal outputted fromthe quantization unit 135 or the space domain quantization unit 137, thequantization unit 135 and the space domain quantization unit 137 may beomitted.

Each signal passed through the quantization unit 135 and the spacedomain quantization unit 137 may passed through the reorder unit 170 andthe entropy encoder 180, thereafter.

The decoder 150 may separate a signal in the same scheme as a scheme theencoder 130 uses, using the received signal separation information.

A domain (boundary domain) quantized by the encoder 130 in the spacedomain may be inverse quantized by the decoder 150 in the space domain,and a domain (non-boundary domain) transform encoded and quantized inthe frequency domain by the encoder 130 may be inverse quantized in thefrequency domain and then inverse encoded by the decoder 150.

The decoder 150 may restore the original differential image block byperforming the inverse quantization, inverse DCT, and space domaininverse quantization with respect to a signal transform encoded andquantized by the encoder 130.

The decoder 150 may restore the differential image block using thesignal separation information indicating that the differential imageblock is separated into the non-boundary domain and the boundary domain.

The decoder 150 may include the signal separator 151, an inversequantization unit 153, an inverse transform decoder 155, and a spacedomain inverse quantization unit 157.

The signal separator 151 may separate the signal that is transformencoded and quantized by the encoder 130 into the non-boundary domainand the boundary domain, using the signal separation information.

The space domain inverse quantization unit 157 may inverse quantize aboundary domain signal in the space domain.

The inverse quantization unit 153 may inverse quantize a non-boundarydomain signal in the frequency domain.

The inverse transform decoder 155 may perform inverse DCT with respectto the inverse quantized non-boundary domain signal.

The reorder unit 170 may reorder each signal that quantized in thefrequency domain and quantized in the space domain.

During the reordering, the reorder unit 170 may use a zigzag scanningscheme generally used with respect to the boundary domain quantized inthe space domain, and may use a scanning scheme that scans whilecircling around in a spiral starting from a boundary line, that is, aline separating the boundary domain and the non-boundary domain.

Generally, an image signal may have a characteristic of graduallychanging based on the boundary line. Thus, in a case of scanning whilecircling around in a spiral starting from the boundary line, signalshaving similar magnitudes may be grouped to enhance an efficiency of animage encoding.

The entropy encoder 180 may perform an entropy encoding using outputs ofthe quantization unit 135 and the space domain quantization unit 137, ormay perform the entropy encoding using an output of the reorder unit170.

The above-described procedure in the video encoding apparatus may beapplied to a decoding in a video decoding apparatus corresponding to thevideo encoding apparatus.

FIG. 2 through FIG. 5 are diagrams illustrating that the video encodingapparatus of FIG. 1 separates a differential image block into anon-boundary domain and boundary domain, based on a form of boundaryline included in the differential image block.

Referring to the left diagram of FIG. 2, it may be assumed that aboundary line 210 is included in the differential image block having asize of N×M, and the boundary line 210 is even with a boundary line 230of a boundary domain as illustrated in the right diagram. Since theboundary domain may not need to be processed, the encoder 130 may notperform a quantization with respect to the boundary domain in theboundary domain, and perform, with respect to all blocks inside of thedifferential image block, the transform encoding by the transformencoder 133 and the quantization in the frequency domain by thequantization unit 135.

Referring to FIG. 3, a boundary line 310 inside of the differentialimage block may not be even with a boundary line 330 of a boundarydomain 340.

When the boundary line 310 is included in a boundary domain 320 insideof the differential image block having a size of N×M as illustrated inthe left diagram, the boundary line 310 may not be even with theboundary line 330 of the boundary domain 340 as illustrated in the rightdiagram.

Thus, the signal separator 131 may set a shaded portion as the boundarydomain 340 so that a number of blocks included in the boundary domainmay be a minimum.

The quantization in the space domain may be performed with respect tothe boundary domain 340 by the space domain quantization unit 137. Thetransform encoding by the transform encoder 133 and the quantization inthe frequency domain by the quantization unit 135 may be performed withrespect to the remaining domain except for the boundary domain 340, thatis, the non-boundary domain.

Referring to FIG. 4, the boundary line inside of the differential imageblock may be formed diagonally. Similar to the case of FIG. 3, thesignal separator 131 may set the boundary domain so that a number ofblocks included in the boundary domain including the diagonal boundaryline may be a minimum. The descriptions described with reference to FIG.3 may be referred to for further detailed operation.

Referring to FIG. 5, the boundary line inside of the differential imageblock may be formed to be a curve. Similar to the case of FIG. 3, thesignal separator 131 may set the boundary domain so that a number ofblocks included in the boundary domain including the curved boundaryline may be a minimum. The descriptions described with reference to FIG.3 may be referred to for further detailed operation.

FIG. 6 is a block diagram illustrating a video encoding apparatusaccording to another embodiment of the present invention. FIG. 6 mayillustrate the video encoding apparatus combining an adaptive blockpartition (ABP) scheme with the movement prediction unit 111, themovement compensator 113, the transform encoder 133, and the inversetransform decoder 155 described with reference to FIG. 1.

Referring to FIG. 6, the video encoding apparatus may include an ABPprediction unit 610, a subtracter 620, an encoder 630, an adder 640, afilter 660, a reorder unit 670, and an entropy encoder 680.

When the ABP prediction unit 610 generates a prediction image using anABP movement prediction unit 611, the ABP prediction unit 610 may needto transmit, to a decoder 650, block separation information includinginformation associated with the ABP.

Since a partition plane of the differential image block of FIG. 2 may bea type of a boundary plane, the partition plane may be used instead ofsignal separation information.

When the ABP prediction unit 610 uses the ABP movement prediction unit611 while predicting a movement, the ABP prediction unit 610 may need tosend the block separation information to the decoder 650. The encoder630 may need to send the signal separation information to the decoder650.

The block separation information may be a target for encoding, and maycorrespond to information about a partition in a form of N×16 or 16×Nwith respect to a macro block being a basic unit of encoding anddecoding in a coder-decoder (CODEC).

The block separation information may be determined through an ABPmovement prediction unit 611 and an ABP movement compensator 613 of theABP prediction unit 610, and may be entropy encoded through the entropyencoder 680.

Depending on cases, the decoder 650 may receive, as the block separationinformation, block separation information entropy encoded in the entropyencoder 680.

The ABP prediction unit 610 may be substituted with the image predictionunit 110 of FIG. 1.

The encoder 630 may include a signal separator 631, an adaptivetransform encoder 633, a quantization unit 635, and a space domainquantization unit 637.

The signal separator 631 may separate the differential image block intoa non-boundary domain and a boundary domain, based on a boundary lineincluded in the differential image block. Here, the differential imageblock may indicate a difference between an original image and aprediction image with respect to the original image.

The signal separator 631 may set a domain excluding the boundary lineincluded in the differential image block as the non-boundary domain, andmay set the domain including the boundary line as the boundary domain.

The adaptive transform encoder 633 may perform a transform encoding withrespect to the non-boundary domain, using a DOT.

The quantization unit 635 may quantize an output of the adaptivetransform encoding unit 633 in a frequency domain.

The space domain quantization unit 637 may quantize the boundary domainin a space domain.

The decoder 650 may restore the differential image block using signalseparation information indicating that the differential image block isseparated into the non-boundary domain and the boundary domain, andblock partition information indicating that the non-boundary domain andthe boundary domain are separated by the ABP.

An adaptive inverse transform decoder 653 may perform an adaptiveinverse transform decoding after an inverse quantization with respect tothe frequency domain in the same manner as the inverse quantization unit153 performs in the frequency domain of FIG. 1, using adaptive encodinginformation received from the encoder 630 and based on the correspondingencoding scheme, and may perform an inverse quantization with respect tothe space domain in the same manner as the space domain inversequantization unit 157 performs.

Descriptions described with reference to FIG. 1 may be referred to forother components of FIG. 6 having the same name as in FIG. 1.

The above-described procedure in the video encoding apparatus may beapplied to a decoding in a video decoding apparatus corresponding to thevideo encoding apparatus.

FIG. 7 and FIG. 8 are diagrams illustrating that the video encodingapparatus of FIG. 6 separates a differential image block into anon-boundary domain and boundary domain, using an adaptive blockpartition and based on a form of boundary line included in thedifferential image block.

Referring to FIG. 7, it may be assumed that a boundary line 710 isincluded in the differential image block having a size of N×M, and theboundary line 710 is even with a boundary line 720 of a boundary domain(P1) 730 as illustrated in the right diagram.

In this case, the video encoding apparatus may not perform thequantization in the space domain by the space domain quantization unit635 with respect to the boundary domain (P1) 730, and may perform, withrespect to all blocks in the differential image block, the adaptivetransform encoding by the adaptive transform encoder 633 and thequantization in the frequency domain by the quantization unit 635.

Referring to FIG. 7, in the present embodiment, by performing atransform encoding adaptively to a location of a boundary lineregardless of a location of the boundary line 710, the boundary line 720may not included inside of the transform encoded domain, and thetransform encoding may reflect a characteristic of a differentialsignal.

Here, when a size of the differential image block is N×M, and a size ofthe boundary domain (P1) is N×m, the video encoding apparatus mayperform the transform encoding with respect to N×m in a case of theboundary domain (P1), and may perform the transform encoding withrespect to N×(M−m) in a case of the non-boundary domain (P2).

Referring to FIG. 8, a boundary line inside of the differential imageblock may be formed diagonally.

When a diagonal boundary line 810 is included in a boundary domain (P1)820 inside of the differential image block having a size of N×M, thediagonal boundary line 810 may not be even with a boundary line of aboundary domain (P1) in the differential image block as illustrated inthe right diagram.

Thus, the signal separator 631 may set a shaded portion as the boundarydomain (P1) so that a number of blocks included in the boundary domainmay be a minimum.

The quantization in the space domain may be performed with respect tothe boundary domain (P1) by the space domain quantization unit 635. Theadaptive transform encoding by the adaptive transform encoder 633 andthe quantization in the frequency domain by the quantization unit 635may be performed with respect to the remaining domain, that is, thenon-boundary domain (P2).

FIG. 9 is a block diagram illustrating a video encoding apparatusaccording to still another embodiment of the present invention.

Referring to FIG. 9, the video encoder 930 may include a signalseparator 931, a transform encoder 933, a quantization unit 935, and aspace domain quantization unit 937.

The signal separator 931 may separate a differential image block into anon-boundary domain and a boundary domain, based on a boundary lineincluded in the differential image block. Here, the differential imageblock may indicate a difference between an original image and aprediction image with respect to the original image.

The transform encoder 933 may perform a transform encoding with respectto the non-boundary domain and the boundary domain quantized in a spacedomain, using a DOT.

The quantization unit 935 may quantize an output of the transformencoding unit 933 in a frequency domain.

The space domain quantization unit 937 may quantize the boundary domainin the space domain.

As described above, the differential image block indicating a differencebetween the original image and the prediction image with respect to theoriginal image may be separated into two domains through the signalseparator 931. Thereafter, to induce a characteristic of the boundarydomain to be similar to a characteristic of the non-boundary domainaround the boundary domain, the encoder 930 may perform, with respect tothe boundary domain, a space domain quantization by the space domainquantization unit 937.

Generally, the boundary domain may have a higher energy compared to thenon-boundary domain, the space domain quantization unit 937 maynormalize the boundary domain through the quantization in the spacedomain so that the energy of the boundary domain may be similar to theenergy of the non-boundary domain around the boundary domain.

The encoder 930 may perform the quantization in the space domain withrespect to the boundary domain before performing the transform encoding,to enhance a correlation between the non-boundary domain and theboundary domain of the differential image block.

As described above, by enhancing the correlation between thenon-boundary domain and the boundary domain, a number of coefficients tobe encoded after the quantization by a characteristic of a DCT may bereduced, and a compression efficiency of the video encoding may beenhanced.

An inverse quantization unit 953 in a decoder 950 may inverse quantizethe non-boundary domain in the frequency domain with respect to areceived signal.

An inverse transform decoder 955 may perform an inverse DCT (DCT⁻¹) onboth the boundary domain and the non-boundary domain inverse quantizedin the frequency domain through the inverse quantization unit 953.

In this instance, the inverse quantization may be performed by theinverse quantization unit 953, and the inverse transform encoding may beperformed by the inverse transform decoder 955.

The non-boundary domain and the boundary domain may be separated, in thesame scheme as a scheme used by the encoder 930 and using signalseparation information transmitted from the encoder 930.

Thereafter, a space domain inverse quantization unit 957 may perform theinverse quantization in the space domain with respect to the boundarydomain quantized by the decoder 950 in the space domain.

The space domain inverse quantization unit 957 may inverse quantize theboundary domain in the space domain.

The decoder 950 may include a signal separator 951, the inversequantization unit 953, the inverse transform decoder 955, and the spacedomain inverse quantization unit 957, corresponding to the encoder 930.

The signal separator 951 may separate, into the boundary domain and thenon-boundary domain, the signal separation information received from theencoder 930.

A movement prediction unit 911 and a movement compensator 913 in animage prediction unit 910 may be replaced by the ABP movement predictionunit 611 and the ABP movement compensator 613 of FIG. 6.

Components described with reference to FIG. 1 may be referred to fordescription of other components including a reorder unit 970 and anentropy encoder 980.

Procedures of the above-described video encoding apparatus may beapplied to a video decoding apparatus corresponding to the videoencoding apparatus.

FIG. 10 is a diagram illustrating that the video encoding apparatus ofFIG. 9 separates a differential image block into a non-boundary domainand boundary domain, based on a form of boundary line included in thedifferential image block.

Referring to FIG. 10, when a boundary line 1010 is included in aboundary domain 1020 inside of the differential image block having asize of N×M as illustrated in the left diagram, the boundary line 1010may not be even with a boundary line 1030 of a boundary domain 1040 asillustrated in the right diagram.

Thus, the signal separator 931 may set a shaded portion as the boundarydomain 1040 so that a number of blocks included in the boundary domainmay be a minimum. Energy with respect to the boundary domain and energywith respect to the non-boundary domain may be obtained.

The space domain quantization unit 937 may obtain a quantization valuein a space domain enabling the energy with respect to the boundarydomain to be normalized to the energy with respect to the non-boundarydomain, and may perform the quantization in the space domain only withrespect to the boundary domain. Thereafter, the encoder 930 may performthe transform encoding and the quantization in the frequency domain withrespect to all domains in the differential image block as illustrated inthe right diagram.

FIG. 11 is a diagram illustrating a scanning scheme with respect to aquantization result in a case of performing a space domain quantizationin FIG. 10.

When a boundary line is included in the differential image blockincluding the differential signal as illustrated in FIG. 11, the encoderin the video encoding apparatus may set the boundary domain, and thenmay perform the quantization in the space domain with respect to theboundary domain.

Thereafter, the reorder unit 970 may scan a coefficient quantized in aspiral based on a boundary line 1110. Generally, a scanning result inwhich signals having similar energy are grouped according to acharacteristic of a video signal gradually changing around the boundaryline may be obtained.

FIG. 12 is a flowchart illustrating a video encoding method according toan embodiment of the present invention.

Referring to FIG. 12, in operation 1210, the video encoding apparatusmay receive, from a subtracter, a differential image block generatedusing an original image and a prediction image.

In operation 1220, a video encoding apparatus may separate thedifferential image block into a first domain and a second domain, basedon a boundary line included in the differential image block. Here, thedifferential image block may indicate a difference between the originalimage and the prediction image.

Here, the first domain indicates a domain excluding the boundary line,that is a non-boundary domain, and the second domain indicates a domainincluding the boundary line, that is a boundary domain.

In operation 1220, the video encoding apparatus may set the domainexcluding the boundary line included in the differential image block asthe non-boundary domain, and may set the domain including the boundaryline as the boundary domain.

In operation 1220, the video encoding apparatus may separate thedifferential image block into the non-boundary domain and the boundarydomain so that a number of blocks included in the boundary domain may bea minimum.

In operation 1230, the video encoding apparatus may perform a transformencoding with respect to the non-boundary domain, using a DOT.

After the video encoding apparatus quantizes a transform encoded resultin a frequency domain in operation 1240, the video encoding apparatusmay quantize the boundary domain in a space domain.

In operation 1260, the video encoding apparatus may perform an entropyencoding using a result quantized in the frequency domain and a resultquantized in the space domain.

In operation 1270, the video encoding apparatus may restore thedifferential image block using signal separation information indicatingthat the differential image block is separated into the non-boundarydomain and the boundary domain.

The signal separation information may include at least one of coordinateinformation indicating locations of the non-boundary domain and theboundary domain, and an indicator indicating a domain to which eachblock included in the non-boundary domain and the boundary domainbelongs, between the non-boundary domain and the boundary domain.

The above-described exemplary embodiments of the present invention maybe recorded in non-transitory computer-readable media including programinstructions to implement various operations embodied by a computer. Themedia may also include, alone or in combination with the programinstructions, data files, data structures, and the like. Examples ofnon-transitory computer-readable media include magnetic media such ashard disks, floppy disks, and magnetic tape; optical media such as CDROM disks and DVDs; magneto-optical media such as optical disks; andhardware devices that are specially configured to store and performprogram instructions, such as read-only memory (ROM), random accessmemory (RAM), flash memory, and the like. Examples of programinstructions include both machine code, such as produced by a compiler,and files containing higher level code that may be executed by thecomputer using an interpreter. The described hardware devices may beconfigured to act as one or more software modules in order to performthe operations of the above-described exemplary embodiments of thepresent invention, or vice versa.

Although a few embodiments of the present invention have been shown anddescribed, the present invention is not limited to the describedembodiments. Instead, it would be appreciated by those skilled in theart that changes may be made to these embodiments without departing fromthe principles and spirit of the invention, the scope of which isdefined by the claims and their equivalents.

The invention claimed is:
 1. A method of decoding a video with a videodecoding apparatus, comprising: determining whether a current block is afirst block with a size that is not a minimum size (4×4) or a secondblock with a size that is a minimum size (4×4); when the current blockis the second block, obtaining, from a bitstream, information indicatingwhether the current block is inverse-transformed or not, wherein theinformation is not signaled for the first block and is signaled for thesecond block; performing a dequantization on residual coefficientsrelating to the current block; obtaining a residual image by performing,based on the information indicating whether the current block isinverse-transformed or not, an inverse-transform on dequantized residualcoefficients; obtaining a prediction image relating to the current blockbased on prediction mode information, the prediction mode informationindicating an intra mode or an inter mode; and generating areconstruction image using the residual image and the prediction image.2. The method of claim 1, wherein an encoded image containing thecurrent block is partitioned into a plurality of blocks, part of theblocks are not inverse-transformed, the remaining blocks areinverse-transformed.
 3. The method of claim 1, wherein the informationindicating whether the current block is inverse-transformed or not isspecified by coordinate information indicating a location of the currentblock.
 4. The method of claim 1, wherein a size or a shape of thecurrent block is determined based on block partition information whichis signaled from the bitstream.
 5. A method of encoding a video with avideo encoding apparatus, comprising: obtaining a prediction imagerelating to a current block based on prediction mode informationrelating to the current block, the prediction mode informationindicating an intra mode or an inter mode; determining whether thecurrent block is a first block with a size that is not a minimum size(4×4) or a second block with a size that is a minimum size (4×4); whenthe current block is the second block, encoding, into a bitstream,information indicating whether the current block is inverse-transformedor not, wherein the information is not signaled for the first block andis signaled for the second block; performing a dequantization onresidual coefficients relating to the current block; obtaining aresidual image by performing, based on the information indicatingwhether the current block is inverse-transformed or not, aninverse-transform on dequantized residual coefficients; generating areconstruction image using the residual image and the prediction image.